High-frequency alternator



Feb. 7, 1928. 1,658,488

M. LATOUR HIGH FREQUENCY ALTERNATOR Filed Sept. 1 1921 HTTORMY PatentedFeb. 7, 1928.

UNITED STATES 1,658,488 PATENT OFFICE.

HARIUS LATOUR, OF PARIS, FRANCE, ASSIGNOR T LATOUR CORPORATION, OFJERSEY oI'rY, NEW JERSEY, A c0 HIGH-FREQUEN Application filed September1, 1921, Serial RPORATION OF DELAWARE.-

CY ALTERNATOR.

No. 497,615, and in France August 10, 1915.

(GRANTED UNDER. THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. L,1313.)

-The present invention relates to improvements in high-frequencyalternator's comprising a rotor having laminated teeth but no winding,and aims at overcoming the difliculties met in the lodging of the statorwinding when high frequencies are sought by decreasing the polar pitchof such machines. It will be best understoodby referring to theaccompanying drawlng, in which Figure 1 illustrates a usual type ofconstruction of such machines;

Figure 2 illustrates a high-frequency alternator constructed inaccordance with the present invention.

In Figure 1, the rotor 1 comprises only laminated teeth and empty slots.The stator 2 comprises a number of teeth 3 having, at the air-gap, awidth equal to that of the rotor teeth. The stator 2 also comprises anumber of slots 4 to accommodate the stator winding, a portion of whichis shown in cross-section. 7

As is well-known, the magnetic flux which is embraced by the statorwinding varies according to whether the laminated rotor teeth or theempty rotor slots are facing the statorteeth 3, and there is generated,in the stator winding, an electromotive force the frequency of which isdetermined solely v by the number of rotor teeth and the peripheralspeedof the rotor.

herefore, when itis desired to construct a machine of this'type forhigher frequencies, one must resort to either an increase. in peripheralspeed or a decrease in polar pitch. Now, for mechanical reasons, it isnecessary not to increase the peripheral speed beyond certain limitswhich are ver soon exhausted in One 40 high-frequency alternatordesigning. must therefore resort to a decrease in the polar pitch. As aconsequence of this procedure, following a certain decrease itnecessarily results that the stator slot dimensions become toorestricted to properly accommodate the stator winding. For exam le, ifWe wish to construct a 50,000 cyc e alternator havin a peripheral speedof 150 meters per secon the resulting space available for both a toothand a slot is but 3 millimeters. While these dimensions are stilladmissible for the rotor teeth since the rotor carries no winding, theyare inadequate for the stator teeth owing to the fact that the latterhave to carry a winding.

Figure 2 illustrates an example ofhow the present invention proceeds inovercoming this obstacle to increasing the frequency by polar pitch.

In Figure the number of laminated rotor teeth on the rotor 1', as wellas the angular span thereof, is the same as that of the rotor 1 ofFigure 1. In order to obtain adequate stator winding space, it will benoted, however, that for every group of p rotor teeth bounded by any twodot-and-dash lines vertically joining Figures 1 and 2, a number equal to(p-n) adjacent stator teeth have been omitted in Figure 2; In

the specific case illustrated by Figures 1 I.

and 2, 72 3, and n=1. teeth and the peripheral speed remaining the sameas in Figure 1, it follows, from What has been stated above, that thefrequency will be the same but with this advantage: The stator slotdimensions, and hence the space available for the accommodation of thestator winding, are thereby greatly increased.

aving described my invention, what I claim is:

1. In a dynamo-electric machine, in combination, a rotating elementhaving groups of teeth with p teeth per group, and a stationary elementcooperating therewith having groups of teeth with pm teeth per group,where 32 is an integer not greater than five, and a is an integer lessthan 12, the teeth of both elements being of the same width at the airgap.

- 2. In a high frequency dynamo-electric The number of rotor y machine,a rotor member comprising a plu rality of evenly spaced teeth with slotstherebetween, a stator member comprising a plurality of evenly spacedteeth with slots therebetween, the teeth of both members having the samewidth at the air gap, and a winding arranged in said slots, the width ofeach slot at the air gap in said stator member being at least equal tothe combined width of-a tooth and a slot on said rotor member, wherebysufficient winding space is provided for said winding.

3. In a high-frequency dynamo-electric machine, a rotor membercomprising a plurality of evenly spaced teeth, the frequency of themachine being equal 'to theproduct slots, the number of teeth on saidstator of the number of said teeth and the number member being less thanthe number of teeth 10 of revolutions per second of said rotor, a onsaid rotor member, whereby increased stator member Comprising aplurality of winding space is provided on said stator evenly spacedteeth with slots therebetween, member for said winding.

the Width of said stator teeth being sub- In testimony whereof I afiixmy signature. stantially' equal to the Width of said rotor teeth, and awinding arranged in said stator MARIUS LATOUR.

